Error concealment in digital transmissions

ABSTRACT

A method is provided for transmitting or storing, over an interference affected channel, digital audio signals that have been subjected to data reduction, resulting in a reduced data, digital audio signal that is present in at least one of the time domain and spectral domain, depending on source coding. An interfered-with signal section is detected in the reduced data, digital audio signal at a receiving end. The interfered-with reduced data, digital audio signal section is masked by one of (a) muting only interfered-with spectral values or subbands, or groups of spectral values or subbands in the signal section and (b) replacing only interfered-with spectral values or subbands, or groups of spectral values of subbands in the signal section with a signal component form the same channel or an adjacent channel including at least one of time domain sampled values, spectral domain sampled values, scale factors, and control information, depending on the source coding of the reduced data, digital audio signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of Ser. No. 09/637,653 filed Aug. 11, 2000 nowU.S. Pat. No. 6,351,720 which is a continuation of Ser. No. 09/345,546filed Jun. 29, 1999 now abandoned which is a continuation of Ser. No.08/778,949, filed Jan. 6, 1997, which issued as U.S. Pat. No. 6,006,173,which is a continuation of Ser. No. 08/648,484, filed May 15, 1996, nowabandoned, which is a continuation of Ser. No. 07/962,216, filed Jan.26, 1993 now abandoned, which claims priority through PCT/EP92/00754,filed Apr. 3, 1992, which claims priority though German PatentApplication P4111131.1, filed Apr. 6, 1991.

BACKGROUND OF THE INVENTION

The invention relates to a method of transmitting or storing, over aninterference affected channel, digital audio signals, whereintransmission errors are detected at the receiving end and corrected ifnecessary or masked, with the masking being effected in that theinterfered-with signal section is muted or replaced by a signalpreceding the interfered-with signal section in the same channel or by asynchronous, not interfered-with signal section of an adjacent channel.Such a method is disclosed in German Patent DE 3,638,922.C2.

In digital audio signal transmissions and storage, the received andread-out audio signals, if they contain bit errors, may either be notdecodable at all or not decodable in part after all error detection anderror correction methods have been exhausted. In that case, it is thecustom to switch to a decoder for muting over a broad band in such a waythat for a certain time period the entire signal is set at 0. In thecase of digital audio signals transmitted by radio, this case occursrelatively frequently at the fringes of the reception area which isextremely annoying particularly in connection with mobile reception. Thesame applies for audio signal storage if the tape material or audioheads are worn to a degree that exceeds a tolerance value.

To reduce the annoying effect of missing signals in radio transmissions,German Patent DE 3,638,922.C2 discloses a mutual offset in time betweenthe left and right stereo channels and, if there is an uncorrectablesignal interference, placing the complementary stereo informationtransmitted at an earlier or later point in time instead of theinterfered-with original information. Although the complementary stereoinformation is not identical with the associated, interfered-withoriginal information, but is connected with it only by way of left-rightcorrelation, such a substitution is acceptable in any case for a shortperiod of time since direction and distance perception as well as theperception of spatial relationships are subject to a certain inertia inthe human ear. However, if such a masking technique is employed for alonger period of time, the stereophonic impression is lost, since themasking always covers the full bandwidth of the interfered-with signaland therefore also replaces spectral signal components that did notsuffer interference.

SUMMARY OF THE INVENTION

In contrast thereto, it is the object of the invention to provide, in amethod of the above-mentioned type, a subjectively better masking oferrors which permits better reconstruction of the interfered-withoriginal audio event and, particularly also during longer use, maintainsthe stereophonic impression.

The above and other objects are accomplished according to the inventionby the provision of a method of transmitting or storing, over aninterference affected channel, digital audio signals that have beensubjected to data reduction to result in a reduced data, digital audiosignal that is present in at least one of the time domain and spectraldomain, depending on source coding, the method comprising the steps of:detecting an interfered-with signal section in the reduced data, digitalaudio signal at a receiving end; and masking the interfered-with reduceddata, digital audio signal section by one of (a) muting onlyinterfered-with spectral values or subbands, or groups of spectralvalues or subbands in the signal section and (b) replacing onlyinterfered-with spectral values or subbands, or groups of spectralvalues or subbands on the signal section with a signal component fromthe same channel or an adjacent channel including at least one of timedomain sampled values, spectral domain sampled values, scale factors,and control information, depending on the source coding of the reduceddata, digital audio signal.

The invention is based on the consideration of intentionally muting,repeating, estimating or replacing for a certain period of time onlythose spectral components of a complete audio signal that have actuallyexperienced interference. The invention takes advantage of the fact thatreduced data, digital audio signals (i.e., digital audio signalssubjected to known data reduction processes) are present in the time andspectral domains, depending on whether they are subdivided into subbands(subband coding) or into spectral values (transformation coding). Thefollowing masking strategies can be employed:

1. Muting

With this masking strategy, only those spectral components of theinterfered-with signal are muted which have actually been interferedwith. Depending on the source coding method employed, these may beindividual subbands or spectral values or groups of subbands or spectralvalues of a digital audio signal that has been subdivided into nsubbands or spectral values, with n being a value equal to or greaterthan 1.

2. Repeating

With this masking strategy, components of the same channel signal areemployed as substitutes for the interfered-with signal components, whichhereinafter will be called “repeating.” Depending on the source codingmethod employed, the components to be repeated may be individualsubbands or spectral values or groups of subbands or spectral values ofa digital audio signal that has been subdivided into n subbands orspectral values, with n again being a value equal to or greater than 1.Again depending on the source coding method employed, these componentsmay be composed of synchronous or spectral sample values as well ascontrol informations or scale factors. The repetition may also beeffected several times.

3. Left-Right Substitution

In this case, synchronous components of the audio signal that arepresent without interference or in processed form in the adjacentchannel are employed as substitutes, which will hereinafter be called“left-right substitution.” The components to be replaced may be, as inthe case of repeating and depending on the source coding methodemployed, individual subbands or spectral values or groups of subbandsor spectral values of an audio signal that has been subdivided into nsubbands or spectral values, with n again being a value equal to orgreater than 1. Again depending on the source coding method employed,these components may be composed of time domain or spectral domainsampled values as well as of control information or scale factors.

4. Estimating

With this masking strategy, not interfered-with or processed componentsof the same channel signal or of the signal from the adjacent channelare utilized by way of estimation (e.g. interpolation) to determine thecomponents required to substitute interfered-with components. Due to theprobability of combinations in the time domain or the spectral domain, aconclusion can be drawn from the use of non-interfered-with or processedspectrally or timely adjacent components of the same channel signal orof a signal from the adjacent channel as to the original content ofinterfered-with components that must be replaced. Depending on thesource coding method employed, the components to be estimated may beindividual subbands or spectral values or groups of subbands or spectralvalues of an audio signal that has been subdivided into n subbands orspectral values, with n here again being a value equal to or greaterthan 1. Again, depending on the source coding method employed, thesecomponents may be composed of time domain or spectral domain sampledvalues as well as of control informations or scale factors. Variousmethods for fading the signals in and/or out can be employed for theabove-mentioned masking strategies. That means that the changeover fromthe not interfered-with component to the replaced or muted componentsand/or from the replaced or muted component to the not interfered-withcomponent is made over a certain transition time and with a certaintransition function so that sudden transitions are avoided.

All of the above-mentioned masking strategies can be combined with oneanother if required.

In connection with the described masking strategies, the invention takesadvantage of certain characteristics of the human sense of hearing. Inthe case of muting, repeating or estimating, the auditorycharacteristics with respect to timely and/or simultaneous maskingthresholds are utilized to the extent that these masking measures remainsubstantially inaudible or hidden as long as they do not exceed acertain time, spectrum and level range.

In the case of the left-right substitution, advantage is taken of thefact that direction and distance perception as well as the perception ofspatial relationships are subject to a certain inertia. This can beutilized to the extent that short-term changes in the display ofdirections and distances of sound sources and of a spatial impressionremain inaudible if they are shorter than a certain length of time anddo not occur too frequently. If these two conditions can be met, thecorrect application of the described masking strategies results in asubstantial improvement over conventional, known masking techniques.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be described in greater detail for one embodimentthereof that is illustrated in sole drawing FIG. 1 which is a blockcircuit diagram for the implementation of the method according to theinvention in the playback channel of a stereo or multi-channel audiotransmission or storage system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the illustrated exemplary case, it is assumed that a digital audiosignal with reduced data is transmitted or stored whose source codeincludes three subbands. In reality the number of subbands isconsiderably higher and amounts to, for example, 32 subbands.

After the digital audio signal has been read out of a memory or receivedover any type of transmission path, the reduced data digital audiosignal under consideration—divided into its three subbands—is present atthe inputs 11, 12 and 13 of a channel decoder 10. Channel decoder 10decodes the channel code of the subband signals at its input and—insofaras this is possible—performs an error correction according to thecapabilities of the respective channel code. The channel decoded subbandsignals are fed via outputs 16, 17 and 18 of channel decoder 10 to amultiplexing device 20 which includes, for each one of the threesubbands, a multiplexer 21, 22 and 23, respectively, that is symbolizedas a selector switch. Multiplexers 21 to 23 are controlled by separateoutputs 31, 32 and 33, respectively, of an analyzer 30 which analyzesthe channel decoded subband signals at outputs 16, 17 and 18 as to howlong the interference contained therein has lasted and what type ofinterference it is. Moreover, analyzer 30 is connected with an output 15of channel decoder 10 so as to obtain information about errors thatchannel decoder 10 was unable to correct, in which subband signal, andat what points in time. This information is also fed to the analyzer ofadjacent channel No. 2. At the same time, analyzer 30 receives thecorresponding information from the output 15 a of the channel decoder ofadjacent channel No. 2.

According to the result of the subband specific analysis performed, theanalyzer decides at which point in time and in which subband therespective multiplexer 21 to 23 is switched from the channel decodedsubband signal at output 16, 17 or 18, respectively, to one of fouralternatively available masking signals. The total of five differentpositions that can be selected for each multiplexer 21 to 23 areindicated in the drawing by the corresponding number of switch terminalson each multiplexer. The mentioned four alternatives correspond to theabove-mentioned masking strategies “muting,” “repeating,” “left-rightsubstitution” and “estimating.” This will be described in greater detailbelow.

To implement the mentioned masking strategies, a memory device 40 isprovided which is controlled through the outputs 51, 52 and 53 of amemory control unit 50, specifically with respect to the respectivesubbands. The input of the memory device is connected with the outputs24, 25 and 26 of multiplexers 21, 22 and 23 of its own channel and withoutputs 16 a, 17 a and 18 a of the channel decoder of the adjacentchannel. Memory device 40 thus stores the processed subband signals ofits own channel as well as the unprocessed subband signals of theadjacent channel, with the latter signals being employed only if they donot contain interference. The processed subband signals of the ownchannel are employed if the “repeating-muting” masking strategy isemployed, while the unprocessed subband signals of the adjacent channelare employed in the “left-right substitution” strategy. For use of the“estimating” masking strategy, memory device 40 receives correspondingestimated values from the outputs 51 to 53 of memory control unit 50,with memory control unit 50 being connected with an output 34 ofanalyzer 30 through which it receives information about the subband inwhich the corresponding estimates are to be made at which times.

The outputs 41 to 49 of the memory device are subdivided into threegroups each having three outputs, with each one of these groups beingconnected with an associated multiplexer 21 to 23. Each group of threeoutputs carries the informations for the respectively associated subbandcorresponding to the three mentioned masking strategies “repeating,”“left-right substitution” and “estimating.” To implement the fourthmasking strategy “muting,” a switch contact of each multiplexer 21 to 23is symbolically connected to ground.

It is understood that multiplexer device 20 is preferably realized bycomputer software, which is also applicable for the remaining functionblocks of the illustrated block circuit diagram.

The subband signals at outputs 24, 25 and 26 of multiplexers 21, 22 and23, respectively, are thus subband signals which either contain nointerference or were subjected to error correction in the channeldecoder or were processed by means of multiplexer device 20 according toone or several of the described masking strategies. The term “processedsubband signal” is intended to indicate this fact. Multiplexer device 20is followed by a source decoder 60 which receives the processed subbandsignals at outputs 24, 25 and 26. In source decoder 60, the processedsubband signals are decoded to yield a digital audio signal which, afterdigital/analog conversion in a converter 70, can be played back, forexample, by way of a channel loudspeaker 80.

It is understood that the block circuit diagram described for only onechannel must be provided for every other channel of a stereo ormulti-channel playback system. The alternatively possible connections inthe block circuit diagrams for the individual channels have already beendescribed.

What is claimed is:
 1. A method for processing interfered-with signals,said signals composed of data representing a plurality of groups of aplurality of subbands comprising a media signal, said method comprisingthe steps of: decoding at least one group of subband signals; storing ina memory a signal portion of at least one group of subbands of processedsignal data; detecting interfered-with signal sections of at least onegroup of subbands with an analyzer; masking said interfered-with signalsections to form at least one masked subband group signal sectionthrough usage of a selectable switch to replace said originalinterfered-with signal sections with a selected masking strategy bychoosing from among two or more of the following alternatives: (i)transmitting said interfered-with signal section without correction;(ii) muting said interfered-with signal section; (iii) replacing saidinterfered-with signal section with said processed signal portion of atleast one group of subbands stored in said memory; or (iv) replacingsaid interfered-with signal section with an estimated signal generatedby an estimator; whereby said at least one masked subband signal sectionis outputted from said switch as said processed signal data; and wherebysaid processed signal is comprised of said processed signal data dividedinto at least one group of subband signal sections interjected whereinterference has been detected and switchably replaced.
 2. The method ofclaim 1, wherein said processed signal data is reduced or compresseddata.
 3. The method of claim 2, including the further step of decodingsaid processed signal with a source decoder for decompressing saidreduced or compressed data whereby said source decoder providessmoothing of transitions in said reduced or compressed data compresseddata signal is processed through a source coding caused by saidinterjection of masked subband group signal sections into said processedsignal.
 4. The method of claim 2, wherein said reduced or compresseddata is processed through a source coder in the time domain and issubdivided into a plurality of groups of subbands through subbandcoding.
 5. The method of claim 2, wherein said reduced or compresseddata signal is processed through a source coder in the spectral orfrequency domain and is subdivided into a plurality of spectral values.6. The method of claim 1, wherein said processed signal is a digitalaudio signal.
 7. The method of claim 1, wherein each said selectableswitch for at least one group of subbands is independent and saidmasking strategies are separately selected and used for at least onegroup of subbands which has interference, as determined by saidanalyzer.
 8. The method of claim 1, wherein said channel decoderperforms error correction and provides signal error information to saidanalyzer.
 9. The method of claim 8, wherein said channel decoderadditionally provides signal error information to a channel analyzer foran adjacent channel.
 10. The method of claim 1, wherein said memoryfurther includes a memory control which receives signals from saidanalyzer, said memory control controlling output of stored signal datafrom said memory.
 11. The method of claim 1, which further includes thestep of fading replaced or muted interfered with signal sections intogroups of subbands of said processed signal data whereby suddentransitions between original and replaced signal data sections areavoided.
 12. A method for processing interfered-with signals receivedover a channel of a multiple, adjacent channel system said signalscomposed of data representing a plurality of groups of a plurality ofsubbands comprising a media signal, said method comprising the steps of:decoding at least one group of subband signals for a first channel;storing in memory a signal portion of at least one group of subbands ofprocessed signal data for said first channel; storing in said memory asignal portion of at least one group of subbands of unprocessed signaldata for said adjacent channel; detecting interfered-with signalsections of at least one group of subbands; masking said interfered-withsignal sections to form at least one masked subband group signal sectionthrough a masking strategy of replacing said interfered-with signalsections with signal portions of said processed signal data from saidfirst channel stored in said memory; whereby said masked subband signalsections are output as at least one group of subbands of said processedsignal data; and whereby said processed signal is comprised of at leastone group of subbands with masked subband signal sections interjectedwhere interference has been detected and replaced.
 13. The method ofclaim 12, wherein said processed signal data is reduced or compresseddata.
 14. The method of claim 13, including the further step of decodingsaid processed signal with a source decoder for decompressing saidreduced or compressed data whereby said source decoder providessmoothing of transitions in said reduced or compressed data caused bysaid interjection of masked subband group signal sections into saidprocessed signal.
 15. The method of claim 14, wherein said masking stepforms said masking subband group signal sections for a length of timeequaling a length of time in which interference occurs.
 16. The methodof claim 12, further comprising the step of dynamically selectingbetween a variety of masking strategies for correcting transmittedsignals, said masking strategies including at least the masking strategyof replacing said interfered-with signal sections with signal portionsof said processed signal data stored in said memory.
 17. The method ofclaim 12, wherein said masking step forms said masking subband groupsignal sections for a length of time equaling a length of time in whichinterference occurs.
 18. A method for processing interfered-with signalsreceived over a channel of a multiple, adjacent channel system, saidsignals composed of data representing a plurality of groups of aplurality of subbands comprising a media signal, said method comprisingthe steps of: decoding at least one group of channel subband signals;storing in a memory a signal portion of at least one group of subbandsof processed signal data for a first channel; storing in said memory asignal portion of at least one group of subbands of unprocessed signaldata for a channel adjacent to said first channel; detectinginterfered-with signal sections of at least one group of subbands withan analyzer; masking said interfered-with signal sections to form atleast one masked subband group signal section through a masking strategyof muting said interfered-with signal sections; whereby said maskedsubband group signal sections are output as at least one group ofsubbands of said processed signal data; and whereby said processedsignal is comprised of at least one group of subbands with maskedsubband group signal sections interjected where interference has beendetected and replaced.
 19. The method of claim 18, wherein said digitalsignal data being processed is reduced or compressed data.
 20. Themethod of claim 19, including the further step of decoding saidprocessed signal with a source decoder for decompressing said datawhereby said source decoder provides smoothing of transitions in saiddata signal sections into said processed signal.
 21. The method of claim18, further comprising the step of dynamically selecting between avariety of masking strategies for correcting transmitted signals, saidmasking strategies including at least the masking strategy of formingmasked subband group signal sections by muting said interfered-withsignal sections.
 22. A method for processing interfered-with signalsreceived over a channel of a multiple, adjacent channel system, saidsignals composed of data representing a plurality of groups of aplurality of subbands comprising a media signal, said method comprisingthe steps of: decoding at least one group of channel subband signals fordecoding a first channel and an adjacent channel; storing in a memory asignal portion of at least one group of subbands of processed signaldata for said first channel; storing in said memory a signal portion ofat least one group of subbands of unprocessed signal data for saidadjacent channel; detecting interfered-with signal sections of at leastone group of subband with an analyzer; masking said interfered-withsignal sections to form at least one masked subband group signal sectionthrough a masking strategy of replacing said interfered-with signalsections with a stored signal portion of at least one group of subbandsof said unprocessed signal data for said adjacent channel stored in saidmemory; whereby said masked subband group signal sections are output asat least one group of subbands of said processed signal data; andwhereby said processed signal is comprised of at least one group ofsubbands with masked subband group signal sections interjected whereinterference has been detected and replaced.
 23. The method of claim 22,wherein said processed signal data is reduced or compressed data. 24.The method of claim 23, including the further step of decoding saidprocessed signal with a source decoder for decompressing said reduced orcompressed data whereby said source decoder provides smoothing oftransitions in said reduced or compressed data caused by saidinterjection of masked subband signal sections into said processedsignal.
 25. The method of claim 22, further comprising the step ofdynamically selecting between a variety of masking strategies forcorrecting transmitted signals, said masking strategies including atleast the masking strategy of masking subband group signal sections byreplacing said interfered-with signal sections with a stored signalportion of at least one group of subbands of said unprocessed signaldata for said adjacent channel stored in said memory.
 26. The method ofclaim 22, wherein said masking step forms said masking subband groupsignal sections for a length of time equaling a length of time in whichinterference occurs.
 27. An apparatus for processing interfered-withsignals composed of data representing a plurality of groups of aplurality of subbands comprising a media signal, said apparatuscomprising: a channel decoder for decoding at least one group of subbandsignals for said channel; a memory for storing a processed signalportion of at least one group of subbands for said channel; a memory forstoring an unprocessed signal portion of at least one group of subbandsof an adjacent channel; an analyzer for detecting interfered-with signalsections of at least one group of subbands; a switch associated with atleast one group of subbands for selectably switching in a replacementsignal for said original interfered-with signal section for at least onegroup of subbands by choosing from among the following alternatives: (i)said original signal section with no replacement; (ii) a muted signalsection; (iii) a processed signal portion of said at least one group ofsubbands of said channel from said memory; (iv) an unprocessed signalportion of said at least one group of subbands of said adjacent channelfrom said memory; or (v) an estimated signal generated by an estimationmeans; whereby said replacement signal sections are outputted from saidswitch as said processed subband group signal data; and whereby saidprocessed digital signal is comprised of said digital signal dividedinto at least one group of subbands with replaced sections switchablyinterjected where interference has been detected.
 28. The apparatus ofclaim 27, wherein said digital signal data being processed is reduced orcompressed data.
 29. The apparatus of claim 28, includes a sourcedecoder for decompressing said processed subband group signal datawhereby said source decoder provides smoothing of s transitions in saiddata caused by said interjection of masked subband group signal sectionsinto said processed signal.
 30. The apparatus of claim 28, wherein saidreduced data signal is processed through a source coder in the timedomain and said signal is subdivided into at least one group of aplurality of said subbands through subband coding.
 31. The apparatus ofclaim 28, wherein said reduced data signal is processed through a sourcecoder in the spectral or frequency domain and said signal is subdividedinto at least one group of a plurality of spectral values, instead ofsaid subbands, through transformation coding.
 32. The apparatus of claim28, wherein said channel decoder additionally provides signal errorinformation to said adjacent channel analyzer.
 33. The apparatus ofclaim 27, wherein said digital signal is a digital audio signal.
 34. Theapparatus of claim 27, wherein each said selectable switch for at leastone group of subbands is independent and said masking strategies areseparately selected and used for said at least one group of subbandswhich has interference, as determined by said analyzer.
 35. Theapparatus of claim 27, wherein said channel decoder performs errorcorrection and provides signal error information to said analyzer. 36.The apparatus of claim 27, wherein said memory further includes a memorycontrol which receives signals from said analyzer, said memory controlcontrolling outputs of said stored signal data from said memory.
 37. Theapparatus of claim 27, which further includes a fading system for fadingsaid replaced signal sections into said processed subband group signaldata whereby sudden transitions between original and replaced signaldata sections are avoided.
 38. The apparatus of claim 27, wherein saidswitch is a multiplexer.
 39. In a method for processing interfered-withsignals composed of data representing a plurality of groups of aplurality of subbands comprising a media signal, the improvementcomprising: detecting at least one interfered-with group of subbands ofa received signal; and, selectably replacing at least a portion of atleast one group of subbands by choosing dynamically one of a variety ofmasking or replacement strategies for said interfered-with group ofsubbands.
 40. In the method of claim 39, the improvement furthercomprising the step of determining at least one of a type and length ofinterference, said replacing step choosing one of said strategies basedon at least one of said type and length of interference.
 41. In themethod of claim 39, the improvement further comprising: estimating acorrected signal for at least one group of subbands of the receivedsignal; and replacing the interfered-with signal section with saidcorrected signal.
 42. In the method of claim 39, the improvement furthercomprising: storing a processed signal section for at least one group ofsubbands; and replacing the interfered-with signal section with saidprocessed signal section for at least one group of subbands.
 43. Anapparatus for processing interfered-with signals composed of datarepresenting a plurality of groups of a plurality of subbands comprisinga media signal, the improvement comprising: a detector for detecting atleast one interfered-with group of subbands of a received signal; and aswitch for selectably replacing at least a portion of at least one groupof subbands by choosing dynamically one of a variety of masking orreplacement strategies for said interfered-with group of subbands. 44.In the apparatus of claim 43, the improvement further comprising ananalyzer for determining at least one of a type and length ofinterference, said switch choosing one of said strategies based on atleast one of said type and length of interference.
 45. In the apparatusof claim 43, the improvement further comprising: an estimator forestimating a corrected signal for at least one group of subbands of thereceived signals, said switch replacing the interfered-with signalsection with said corrected signal.
 46. In the apparatus of claim 43,the improvement further comprising: memory for storing a processedsignal section for at least one group of subbands, said switch replacingthe interfered-with signal section with said processed signal sectionfor at least one subband.
 47. An apparatus for processinginterfered-with signals received over a channel of a multiple, adjacentchannel system said signals composed of data representing a plurality ofgroups of a plurality of subbands comprising a media signal, saidapparatus comprising: a channel decoder for decoding at least one groupof subband signals for a first channel; a memory for storing a signalportion of at least one group of subbands of processed signal data forsaid first channel; a memory for storing a signal portion of at leastone group of subband of unprocessed signal data for said adjacentchannel; an analyzer for detecting at least one interfered-with signalsection of at least one group of subbands; a switch associated with atleast one group of subbands for switching in a replacement signal forsaid at least one interfered-with signal section to form at least onemasked subband group signal section through a masking strategy ofreplacing said interfered-with signal sections with signal portions ofsaid processed signal data from said first channel stored in saidmemory; whereby said at least one masked subband signal sections areoutput as at least one group of subbands of said processed signal data;and whereby said processed signal is comprised of at least one group ofsubbands with masked subband signal sections interjected whereinterference has been detected and replaced.
 48. An apparatus forprocessing interfered-with signals received over a channel of amultiple, adjacent channel system, said signals composed of datarepresenting a plurality of groups of a plurality of subbands comprisinga media signal, said apparatus comprising: a channel decoder fordecoding at least one group of channel subband signals; a memory forstoring a signal portion of at least one group of subbands of processedsignal data for a first channel; a memory for storing a signal portionof at least one group of subbands of unprocessed signal data for achannel adjacent to said first channel; an analyzer for detecting atleast one interfered-with signal section of at least one group ofsubbands; a switch associated with at least one group of subbands forswitching in a replacement signal for said at least one interfered-withsignal section to form at least one masked subband group signal sectionthrough a masking strategy of muting said interfered-with signalsection; whereby said at least one masked subband group signal sectionsare output as at least one group of subbands of said processed signaldata; and whereby said processed signal is comprised of at least onegroup of subbands with masked subband group signal sections interjectedwhere interference has been detected and replaced.
 49. A method forprocessing interfered-with signals received over channel of a multiple,adjacent channel system, said signals composed of data representing aplurality of groups of a plurality of subbands comprising a mediasignal, said apparatus comprising: a channel decoder for decoding atleast one group of channel subband signals for decoding a first channeland an adjacent channel; a memory for storing a signal portion of atleast one group of subbands of processed signal data for said firstchannel; a memory for storing a signal portion of at least one group ofsubbands of unprocessed signal data for said adjacent channel; ananalyzer for detecting at least one interfered-with signal section of atleast one group of subbands; a switch associated with at least one groupof subbands for switching in a replacement signal for said at least oneinterfered-with signal section to form at least one masked subband groupsignal section through a masking strategy of replacing saidinterfered-with signal section with a stored signal portion of at leastone group of subbands of said unprocessed signal data for said adjacentchannel stored in said memory; whereby said at least one masked subbandgroup signal section is output as at least one group of subbands of saidprocessed signal data; and whereby said processed signal is comprised ofat least one group of subbands with masked subband group signal sectionsinterjected where interference has been detected and replaced.